Method for ballasting a vessel



United States Patent 72] inventors DonaldJ.Peters Baltimore; George E. Olseth, Cockeysville, Maryland [21 Appl No 800.291 [22] Filed Feb. 18, 1969 [45] Patented Dec. 1, 1970 [73 I Assignee Harry T. Campbell SonsCorporation Towson, Maryland a corporation of Maryland 1 4] METHOD FOR BALLASTING A VESSEL 5 Claims. No Drawings Primary Examiner- Trygve M. Blix AttorneyCushman, Darby & Cushman ll4/l25 ABSTRACT: A method for ballasting a vessel comprising introducing into a ballast space in said vessel a flowable inert in organic ballast composition comprising water and a mixture of graded aggregate and noncementitious filler, said filler being present in amounts of about 5- 30 weight percent of said mixture. said aggregate'and filler having a specific gravity ranging between about 2.40-2.90. said aggregate and fillei being graded to provide a mixture having minimum percent voids so that when said mixture is combined with water in amounts of 6-25 percent by weight of the total ballast composition, said ballast composition has a density ranging between about l 15- l 60 pounds per cubic foot.

METHOD FOR BALLASTING A VESSEL This invention relates to the hallasting of ships and more particularly to the use of an inert, inorganic ballast composition' of controlled particle size distribution and of exceptionally high density.

Heretofore, it has been a common practice to employ sea water as a ballast for ships although such practice creates certain disadvantages, not the least of which is a severe corrosion problem. Additionally, the use of sea water, because of its proximity in density to fresh water, finds relatively little effective application in situations where the ballast is required to lower the center of gravity, to the desired degree, of cargo ships destined for use in the transportation of low density car go, such as containerized freight,.a portion of which is often stacked above the deck of the cargo ship.

Efforts to overcome the disadvantages attendant with the use of sea water as a ballast agent, have resulted in the utilization of a solid ballast material such as dense concrete slabs and pig iron. While such solid ballast material can eliminate this density problem, its widespread use has been discouraged because of its difficulty to be conveniently placed or removed in the ship, thereby often necessitating its placement in areas which would otherwise be considered as valuable cargo space.

More recent efforts have returned to the concept of utilizing a liquid ballast material of high density which would alleviate the problem of introducing and removing the same from conventional ballast tanks or space in cargo ships, yet provide alteration of the center of gravity of cargo ships to the extent desired.

Representative of such liquid ballast material is one prepared from a high density inorganic material such as baryte which requires relatively large amounts of water in order to achieve the required final density of the ballast composition. This large water requirement is considered disadvantageous in several respects. For instance, the incorporation of large amounts of water in the ballast composition gives rise to a sloshing effect within the ballast space during movement of has to be removed.

It has also been observed that such liquid ballast materials often are contaminated with or contain organic materials. In order to prevent the formation of explosive gases when such contaminated liquid ballast materials are in place, it has been found necessary to admix therewith expensive bacteriostatic agents. Additionally, because of the relatively high water content of these liquid ballast materials, generally in the order of about 25 -30 percent, the corrosive nature thereof is accentuated and to alleviate this problem it has been found necessary not only to include corrosion inhibitors but also, in many instances, to pretreat the space which receives these liquid ballast materials by coating the same with a corrosion inhibiting composition. Obviously, the cost of these additives and coating measures decrease significantly the economic attractiveness of the use of these known liquid ballast compositions with respect to their ease of placement and removal from the ballast area of cargo ships.

It has now been found that the disadvantages associated or experienced with the use of such liquid ballast materials can be overcome by the present invention which utilizes a flowable, inert, inorganic ballast composition prepared from a mixture of graded, normal density aggregate materials and a noncementitious filler. Surprisingly, it has been found that the use of normal density aggregate and filler in accordance with the present invention as opposed to the use of high density inorganic materials of the prior art, requires less water in admixture therewith to attain comparable ballast composition density values.

conventionally established requirements or specifications for a fluid ballastmaterial include the following. considerations. The fluid should not promote the formation of aerobic or anaerobic bacteria and must therefore, if it contains or becomes contaminated with organic materials, to be provided with a bacteriostatic agent. The fluid also must be anticorrosive and should therefore be alkaline in nature. While corrosion inhibitors can be added to achieve anticorrosivity, such inhibitors should not deleteriously affect the action of the bacteriostatic agent or affect the physical properties of the fluid such as its pumpability or the like. If solids are employed in the fluid composition, the fluid should have sufficient viscosity and gel characteristics to minimize settling of solids. Additionally, the thermal expansion characteristics of the fluid should be such that its volumetric expansion should not be greater than 0.4 percent over a temperature range from 32 F. to F. and should be capable of withstanding an ambient temperature of 32 F. without freezing.

. The novel ballast system of the present invention meets substantially all these requirements and as pointed out above overcomes the disadvantages experienced in the use of liquid ballast systems prepared'from high density inorganic materials combined with relatively large amounts of water. The ballast material of the present invention utilizes in admixture with water an inert, inorganic material of controlled particle size distribution having normal density characteristics and which material when so admixed with relatively minor amounts of water imparts to the ballast composition an exceptionally high density.

The inert, inorganic material component of the ballast composition of this invention-comprises a mixture of graded aggregate and noncementitious filler, the filler being present in amounts of about 5-30 weight percent of the mixture. The aggregate and filler are characterized as exhibiting normal density properties, i.e. the specific gravity thereof ranges between about 2.40 to about 2.90. It is also essential that the aggregate and filler be graded, i.e. have a controlled particle size distribution, to provide a mixture having minimum percent voids so that when the mixture is combined with water in amounts of 6-25 percent by weight of the total ballast composition, the ballast composition has a density ranging between about to about pounds per cubic foot. The novel ballast composition of this invention is generally alkaline by nature rather than acidic and does therefore exhibit favorable anticorrosive characteristics although it will be recognized that if desired enhanced anticorrosive properties can be attained by the inclusion therein of conventional corrosion inhibitors or the implementation of conventional anticorrosion measures. The novel ballast composition of this invention is capable of being pumped by concrete pumps and since it contains relatively little water, essentially little or insignificant settling occurs. Further, because the ballast composition contains only minor amounts of water, it does not, when in place, produce or occasion a sloshing phenomenon. To the contrary after placement in the ballast space, the hydraulic properties imparted thereto during placement essentially disappear and the ballast composition assumes the characteristics of an essentially nonflowable, nonhydraulic material which can, nevertheless be removed by a simple water flushing operation using a stream of water under conventional pressures ranging from about 40-100 pounds per square inch. This characteristic, of course, permits removal of the ballast composition from selective areas within the total ballast space and substantially eliminates any concern of loss or outflow of the entire or substantial amounts of the ballast composition in the event of damage to the ballast tank or space, which loss or outflow is a definite possibility when a ballast composition retains essentially its liquid characteristics when in place. Further, the thermal expansion properties of the ballast material of this invention meet recognized standards and the volumetric expansion characteristics thereof are in the order of about 0.1 percent. As indicated above, the density of this novel ballast material ranges between about 1 15-160 pounds per cubic foot.

The aggregate component of the ballast composition of this i when mploying a mixture of aggregate and noncementiinvention can be any commercially available inert, inorganic itiOllS filler, as in mpl s VII-IX wherein the maximum parmiti te i l h as quartz, quartzite, ticle size is essentially less than three-eighths of an inch, the granite, trap rock, limestone and the like. The filler comi gg g preferably has the following Sieve analysis (P ,ponent can be of the same chemical composition as the ag- 5 P g) inch 99 to 100 P 04 50 to 60 P 08 gregate component. Representative filler materials include i- 39 to 49 P 016 35 i0 45 P 030 27 I0 37 P rlimestone from dust collectors, silica flour, slag fines including iceht; 050 to 16 Percent; 0100 T to 2 Percent The filler blast furnace slag fines, boiler slag fines, fines from wet scrub- ;material which is Present in amount of about weight P bers, fly ash or dust from dust collectors. It is essential that the cent of the total y mixture has a Sieve analysis (P fin b i inorganic d noncementitious. 10. passing): 0100 about 95 percent to about 100 percent; 0200 A i di d above h aggregate and fin having a about 80 percent to about 100 percent and 0325 about 40 specific gravity ranging between about 2.40 to about 2.90, are P to abPht T Percent The Specific gravity of the graded to provide a mixture having minimum percent voids so igl'egate and hue! IS and when combined with P that when the mixture is combined with water in amounts of iceht water f h the tota] weight of the composition, the about 6-25 percent by weight of the total ballast composibahflst compo-51mm has a density of about 140 Pounds P tion, the ballast composition has a density of about 115-160 cubic footpounds per cubic foot. The percent or fraction of any given The following EXamPTeS intimate the "f Ofmixtufes of particle size of said aggregate and filler, will of course be deaggregate h htfhcemehhtlous fillets, essehhhhy the same h pendent on a number of easily ascertainable factors such as those described m Exathples v and T sultable 'h the maximum size of particle to be included in the mixture, the hanasuhg cargo Vessels accotdahce wtth the Present apparent specific gravity of the aggregate and filler chosen within the above stated range, and the density of the ballast composition desired also within the above stated range. It has been found convenient to utilize commercially available ag- 5 Example X XI XII gregate and filler which initially substantially pass through a 1 inch screen and which are graded to provide fractions of (a) gg ff fffihffl ff (1) (2) (a) specific sizes, which fractions when mixed together and com- E i n sto g h g y g i g-n- 40 C 1 103,581] W ercen I [ISIS b lned with definite but relatlvelymlnor PIOEJOIUOHS Of water (a) Quamite gmveflwt. perceynt dry 52 0 0 yield a ballast composltlon havmg a density ranging from (p) l i l s p c g l p v (A TM C428)... 6 6 2. 67

about 1 15- 1 60 pounds per cubic foot. Other convenient balgg i i i l fi gg f if'dggifiigiagi 8 166'1 7 last compositions accordlng to this lnventlon can be prepared produce ballast composition 7. 4 18.0 25.0 (h) Density of ballast composition 147. 0 132. 5 125. 0

from graded aggregate and filler initially substantially passing through 541", No.4 and No. 8 U5. sieves. s E

The following examples illustrate the gradation of various 3 5 2 3 3:: ijifl aggregate and noncementitious filler materials in accordance Same as with sieve analysis (percent passing) thereof based on essentially the maximum particle size desired in the total ballast composition.

Any of the above mixtures of graded aggregate and filler can be combined with water in amounts sufficient to produce a ballast composition having a density ranging between about 115-160 lbs/ft in accordance with the following relationship:

Percent A wherein D is the density of the ballast composition within the above stated limits; p,, is the apparent specific gravity of the graded mixture of aggregate and filler ranging between 2.40-2.90 and P is the weight percent of water based on the total weight of the ballast composition.

The ballast compositions of this invention are usefully employed in cargo ships to lower the center of gravity thereof, especially when containerized freight is transported on such ships. The ballast compositions can be prepared by admixing The following examples illustrate the use of graded agthe mixture of aggregate and filler with water in any convengregate and filler to produce the ballast composition of the tional mixing apparatus such as a transit mix concrete truck or present invention. the like. In addition to delivering the ballast material by means of a suitable concrete pump and associated piping to the ballast tank or space, the ballast composition can also be Exam? VII VIII delivered thereto by other conventional means such as belt i conveyors, chutes or the like. (a) Agigregate and filler sieve analysis (percent 1 w claim.

ass ng 1 1 I (bl Limestone (wt. percent dry basls) 10o 0 5| l. A method for ballastlng a vessel comprlslng introducing (c) sum and percent dry has) 0 0 65 into a ballast space in said vessel, a flowable, inert, inorganic (d) Qnartzlte gravel (wt. percent dry basis). (e) Apparent specific gravity (AS'IM C428) (1') Solid density (lbs/I) (g) Dry compacted unit weight (lbs/IN)".

2. s2 2, 82 67 ballast composition comprising water and a graded mixture of 176 1 176-1 l aggregate and noncementitious filler, said filler being present f-g in amounts of about 5-30 weight percent of said mixture, percemvolds'based t X100 i said aggregate and filler having a specific gravity ranging pr is'il'fifilll liiiiiiil fl fiRffifiifiiiifl 14. 0 13.1 10. 0 2.40490 and F glad pmlide (jag i rllvsllt ballast composition (lbs/rm) ture havmg minimum percent volds so that when said mixture 136 is combined with water in amounts of about 6-25 weight per- 1 8 cent based on the total weight of the ballast composition, said 3$: E; ballast composition has a density ranging between about 1 l5- 3 Same as Ex. IV. 75 l 60 pounds per cubic foot.

2. The method of claim 1 wherein water is present in amounts of about -l5 weight percent based on the dry weight of said mixture.

3. The method of claim 1 wherein said aggregate is selected from the group consisting of quartzite gravel, silica sand, limestone and their mixture.

4. The method of claim 1 wherein the size of the particles of aggregate and filler in said mixture is essentially less than one inch.

5. The method of claim 1 wherein the aggregate in said mixture has the following sieve analysis (percent passing): inch 99 to 100 percent; No. 4 50 to 60 percent; No. 8 39 to 49 percent; No. 16 to percent; No. 30 27 to 37 percent; No. 10 to 16 percent; and the filler in said mixture has the following sieve analysis (percent passing): No. 100 about to percent; No. 200 about 80 to 100 percent and No. 325 about 40 to 100 percent; said filler being present in an amount of about 15 weight percent of the dry mixture. 

